^ There are a number of exceptional situations in which GABA has been found to have excitatory effects, mainly during early development. For a review see Marty A, Llano I (June 2005). "Excitatory effects of GABA in established brain networks". Trends Neurosci.28 (6): 284–9. doi:10.1016/j.tins.2005.04.003.PMID15927683.